[Suggestion] Add modifier keys + mouse clicks to screencast keys

[Cub0use]

Detailed description of your suggestion

Add Ctrl, Alt and Shift + mouse clicks to screencast keys

It's something I would have liked to report issue JannisX11/blockbench#1740, and generally would be good for making tutorials since many inputs are click-based.

Showing even normal mouse clicks could be good, but then the screencast could easily get convoluted. Maybe a little wireframe mouse icon in the corner of the canvas would be more fitting, to show pressed mouse buttons with a white overlay.

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While I'm at it, it would be nice to have a setting to change the scale of screencast keys, independently from the interface scale, I find them pretty small.